In modern electronic circuits, power consumption is an increasing concern. Generally, it is desirable to keep the power consumption as low as possible, which for example prolongs the battery lifetime in mobile applications and also reduces problems for example caused by heating of portions of the electronic device due to power dissipation.
Therefore, electronic circuits or portions thereof may be configured to have at least two modes of operation comprising an active mode or state where the electronic device or portion is operating normally and a sleep mode or state where the electronic circuit or portion thereof is inactive and its power consumption is reduced. Such a sleep mode may for example be obtained by separating the respective portion of the electronic circuit from a power supply, reducing the supply voltage of a power supply or connecting the portion of the electronic circuit to a power supply having a reduced supply voltage.
If an electronic circuit portion which is in sleep mode needs to be used, it is “woken up”, i.e. put in the active mode. Depending on the application, the time needed for such a wake-up may be critical. Therefore, to enable the use of such a sleep mode even for applications where time may be critical, there is a need for a fast wake-up of such electronic circuit portions.